Setup standard /dev symlinks

This is a rebase of #5735

After copying allowed device nodes, set up "/dev/fd", "/dev/stdin",
"/dev/stdout", and "/dev/stderr" symlinks.


Fixes #2356
Fixes #5510
Closes #5735

Docker-DCO-1.1-Signed-off-by: Bernerd Schaefer <bj.schaefer@gmail.com> (github: bernerdschaefer)